YOUNG PLANTS often differ both morphologically and physiologically from older plants of the same species. For example, immature trees of various species often have more thorns, greater vigor, and a more erect habit than mature plants (Furr et al., 1947) and different leaf shapes (Stoutemeyer, 1937). Numerous photoperiod-sensitive species do not respond to photoperiodic treatment when very young, and others which display marked sensitivity to day length when young, lose it with age (Naylor, 1953). Sometimes adventitious or juvenile shoots on older plants can be used for propagation, whereas cuttings from branches of mature trees root poorly if at all (Stoutemeyer, 1937; Dermen, 1948). The problem of juvenility is of particular interest in the Para rubber tree (Hevea brasiliensis (Wild. ex. Adr. Juss.) Muell. Arg.), in which cuttings from young trees regenerate roots readily, but cuttings from old trees do not root at all (Baptist, 1939; Muzik, 1953). The rubber tree generally is propagated by budding, but the effect of stock on yield is still unsettled (Dijkman, 1951). Stahel (1947) reported the rooting of cuttings from Hevea trees of seedling origin under a water spray. This paper describes methods to induce the development of adventitious shoots on seedlings and mature trees of Hevea brasiliensis and compares the rooting ability of these shoots to axillary shoots. Such studies are of fundamental interest in relation to the general phenomenon of juvenility in plants as well as of potential practical interest in developing uniform rootstocks for experimental purposes. The long first internode (epicotyl) in seedlings of Hevea brasiliensis has been described by Calvert (1887) and Petch (1911). The length of this internode is fairly constant within a population but mav vary from 12 to 23 cm. in mixed plantings. The buds at the first node are opposite but they are alternate on the rest of the stem, thus making it easy to distinguish this node. The first internode was very useful in the present study because any buds which sprouted in this region must necessarily be of adventitious origin. On ordinary stems it is often difficult to determine the exact origin of new sprouts. MATERIALS AND METHODS.-The stems of rubber seedlings from 3 weeks to 18 months of age were excised at various heights to stimulate bud sprouting. A similar study of grafted plants was also made. Mature clonal trees were laid horizontally